Xiaoyu Mao

Temperature dependence of ministop band in double-slots photonic crystal waveguides

We proposed and fabricated a double-slots photonic crystal waveguides (PCWGs) structure formed by introducing two slots into PCWGs with air-bridge structure on silicon-on-insulator substrate. The mode characteristics of double-slots PCWGs were investigated theoretically and experimentally. The transmission spectra present a sharp and deep dip (22 dB with bandwidth of 6 nm) caused by ministop band in the proposed structure, which is 15 dB deeper than that in the W3 PCWG. Additionally, dependence of the dip on temperature in the double-slots PCWG was measured and a temperature coefficient 0.159 nm/°C can be concluded.

Coupling between even- and oddlike modes in a single asymmetric photonic crystal waveguide

The photonic crystal (PC) is an important structure for realizing optical integrative circuits. Nowadays, most PC based passive devices operate by utilizing the coupling either between several PC waveguides or between PC waveguides and resonance cavities. In this letter, we present a coupling mechanism between even- and oddlike modes in a single asymmetric PC waveguide. Switches based on this coupling phenomenon were validated experimentally. By adjusting the temperature controlled by the thermal resistor, an extinction ratio of 9.1 dB was realized. Our researches provide a potential way of not only guiding but also controlling light in a simple single PC waveguide.

Effects of Structure Parameters and Structural Deviations on the Characteristics of Photonic Crystal Directional Couplers

The effects of structure parameters and structural deviations on the characteristics of photonic crystal directional couplers (PCDCs) were analyzed through a systematic simulation study. The relationship between coupling characteristics and structure parameters was discussed. The results reveal that the remained power in the coupling region is detrimental to reducing the insertion loss of PCDCs, especially for the PCDCs with shorter coupling length. An improved structure, which increases the radii of air holes in the post coupling region, was proposed to suppress the remained power and reduce the insertion loss effectively. The influence of structural deviations, which is caused by fabrication imperfections and results in the mismatch between experimental results and theoretical predictions, was also investigated using statistical methods. The simulation results show that the air hole position misalignment perpendicular to the waveguide direction has the largest effect on the insertion loss of PCDCs, and reducing r/a is helpful to improving the robustness of PCDCs.

Photonic crystal waveguides and their applications Invited Paper

Two-dimensional (2D) slab photonic crystal waveguides (PCWGs) on silicon-on-insulator (SOI) wafer were designed and fabricated. Full photonic band gap, band gap guided mode, and index guided mode were observed by measuring the transmission spectra. Mini-stop-bands in the PCWG were simulated with different structure parameters. Coupling characteristics of PCWG were investigated theoretically considering the imperfections during the fabrication process. It was found that suppressing power reservation effect can realize both short coupling length and high coupling efficiency.

Passive and active performances of slab photonic crystal waveguides

Two dimensional slab photonic crystal waveguides were designed and fabricated. Full photonic band gap, band gap guided mode, and mini-stop-bands were observed. Passive and active performances were investigated theoretically and experimentally.

Degraded Performance of Photonic Crystal Couplers due to Fabrication Imperfections

The influence of fabrication imperfections on the performance of photonic crystal directional couplers (PCDC) with different structure parameters were investigated theoretically. It was found that the air hole position misalignment perpendicular to the waveguide has a more powerful influence on the transmission efficiency of PCDC than other fabrication imperfection factors, and reducing r/a is helpful to improve the robustness of PCDC.

Structure Parameters Dependence of Mini Stop-Bands in Two-Dimensional Photonic Crystal Waveguide

In this paper, we investigate the structure parameters dependence of central frequency as well as bandwidth of mini stop-bands in two-dimensional photonic crystal waveguides.

Research on Slab Photonic Crystal Waveguides

Coupling characteristics and gain performances of slab photonic crystal waveguides were investigated theoretically. The simulation results are reported in this paper.

Optical Gain of INGAASP MQW with Different Photonic Crystal Waveguides

Optical gain spectra of InGaAsP MQW with different PCWG were simulated by considering the variation of group velocity and the natural broadening synthetically. An optimal width of the PCWG was demonstrated for maximum gain enhancement theoretically.

Fluid sensor based on transmission dip caused by mini stop-bands in 2D photonic crystal waveguides

In this paper, we propose a fluid sensor based on transmission dip caused by mini stop-band in 2D photonic crystal waveguides. Simulation results shows that it has large detective range and relative high sensitivity.